A communication system provides for the communication of data between a sending station and a receiving station. The data is communicated between the sending and receiving stations by way of a communication channel that interconnects such stations. Data sourced at the sending station is converted into a form to permit its communication upon the communication channel. And, once delivered to the receiving station, recovery operations are performed upon the communicated data to recover the informational content thereof.
A radio communication system is an exemplary type of communication system. Communication channels defined in a radio communication system are defined upon radio links extending between the sending and receiving stations operable therein.
Because radio channels are utilized to communicate data between the sending and receiving stations, the need otherwise to install fixed, wireline connections to interconnect the sending and receiving stations, and to define communication channels thereon, is obviated. Therefore, infrastructure costs associated with the installation of a radio communication system are generally less than the corresponding infrastructure costs required to install the infrastructure of a wireline communication system. And, mobility can be provided to the communication stations operable in a radio communication system, thereby permitting mobile communications to be effectuated.
A cellular communication system is a type of radio communication system. Cellular communication systems have been installed throughout significant parts of the populated portions of the world. Cellular communication systems are constructed to be operable in compliance with operating specifications of any of various operating specifications.
A cellular communication system includes a network infrastructure that is installed throughout a geographical area that is to be encompassed by the communication system. The network infrastructure typically includes a plurality of fixed-site radio transceivers, referred to as base-transceiver stations, positioned at spaced-apart locations of the geographical area. Each of the base transceiver stations defines a region, referred to as a cell from which a cellular communication system derives its name.
Subscriber stations, usually referred to as mobile stations, positioned within the proximity of individual ones of the base transceiver stations are capable of communications therewith, thereby to permit effectuation of communication of data between the mobile station and a base transceiver station. Generally, a user of a mobile station is permitted access to the communication system to communicate therethrough through the purchase of a service subscription for service in the communication system.
Significant portions of the populated areas of the world are encompassed by cellular communication systems. Users are able to communicate telephonically when positioned in an area encompassed by the network part of a cellular communication system through the purchase of a service subscription for communication services in a system. Different systems, operated by different operators are sometimes overlayed in a single geographical area, providing a user with service selection between two or more separate systems. And, as technological advancements have permitted, successive generations of cellular communication systems have been developed and deployed. New systems that take advantage of new technological advancements are also under development, to be ready for future deployment.
Cellular communication systems are sometimes categorized by generational-type. That is, successive generations of cellular communication systems have been developed and deployed. The general timeline during which the systems are installed, and the technology available for inclusion in the system at the time at which the system initially was available for deployment, is divided into generations.
Systems that were first-installed are sometimes referred to as being of a first-generation (1G). First-generation systems generally make use of conventional, analog communication techniques utilizing frequency-division, multiple-access (FDMA) schemes. A system, referred to as an AMPS (Advanced Mobile Phone Service) system, is exemplary of a first-generation, cellular communication system.
Systems deployed subsequent to first-generation systems and that first incorporated digital communication techniques are sometimes referred to as being of a second-generation (2G). Such systems generally provide for, in addition to conventional voice communications, some data services. A system, referred to as an IS-95 (interim standard-95) system, is exemplary of a second-generation cellular communication system. An IS-95 system utilizes a code-division, multiple-access (CDMA) communication scheme.
Systems, generally related to corresponding 2G systems, but incorporating additional features, particularly improved data communication capabilities, permitted by evolutionary technological advancements, are sometimes referred to as being two-and-a-half generation (2.5G) systems. A cdma2000 system is exemplary of a 2.5 generation communication system.
And, so-called, third-generation (3G) systems are undergoing, or are anticipated to be undergoing, deployment. These systems incorporate additional technological advancements and, generally provide for yet more-extensive data services than predecessor-generation systems. A 3GPP2 (third-generation partnership project two)-promulgated system, referred to as 1×EV-DV (1×Evolution for Data and Voice) is exemplary of a third-generation system predicated upon the cdma2000 system. And, HSDPA (High Speed Downlink Packet Access) in W-CDMA (Wideband-Code-Division, Multiple-Access) is a 3GPP-promulgated system, also exemplary of a third-generation system. These third-generation systems, as well as others, also differ with their 2G and 2.5G predecessors in that shared packet data channels, i.e., packet-switched channels, are to be used pursuant to certain data services.
In contrast, the predecessor systems generally utilize only circuit-switched, or otherwise dedicated, radio channels upon which to effectuate communications. The use of packet-switched channels permits the bandwidth allocated to the communication system to be utilized more efficiently. And, the communication capacity of a communication system that utilizes packet-switched communications is potentially significantly greater than the communication capacity of a corresponding system that utilizes only circuit-switched channels.
Voice over Internet Protocol (VoIP), or, more generally, Voice over Data (VoD), is a communication service that is anticipated to have significant use in mobile communications. Internet access is increasingly becoming ubiquitous, with increasing momentum. The aforementioned third-generation systems are intended to be capable of providing such VoD services.
Various technical issues remain, however. One technical challenge is to fulfill Quality of Service (QoS) requirements for VoIP services. A quality of service is a parameter that represents, according to one, or more, definitional criteria, a minimum service level at which a VoIP, or other, communication service is to be effectuated. The definitional criteria includes, for instance, delay times, error rates, or any other factor that might be determinative of, or have an affect on, the quality of the communication service. And, generally, Quality of Service refers to the ability to support an application requirement with regards to the categories, e.g., of bandwidth, delay, jitter, and traffic loss. The QoS parameters are managed based upon applications.
A subscriber to the communication system might, for instance, subscribe for service at a particular QoS level. For subscriptions at higher QoS levels, higher subscription fees, for instance, are charged by the operator of the communication system. And, in any event, maintenance of at least minimum QQS levels is required to ensure that the communication service is effectuated at least at a selected level. Also, different communication services are categorized differently. A VoIP service is generally prioritized as a highest-priority service. And, out of four defined traffic classes, a VoIP service is defined as conversational traffic that requires low delay and low data loss rates. A VoIP service is a real-time application that is sensitive to jitter.
To ensure that the voice quality level of a VoIP service is of an acceptable level, for instance, the bit error rate (BER) of the communicated frames, or packets, of data should be less than one percent. Maintenance of a frame quality is achieved, for instance by maintaining channel, albeit at the expense of capacity. Data retransmission is an alternative.
A VoIP service also requires the in-sequence delivery of compressed voice packets to maintain communication quality. It would be desirable to assure that voice packets are delivered in-sequence together with adoption of an appropriate retransmission scheme.
An end-to-end QoS architecture includes different QoS services and requirements within an entire network that includes radio access, mobile networks, and wire line core network parts. Different mechanisms are applied on each segment through the entire network by which to satisfy the overall QoS delivery. But, challenging aspects remain with respect to mechanisms by which to support QoS requirements at the radio interface portion of a communication network. And, particularly, a mechanism by which to address maintenance of error rates and delay times remains to be solved.
It is in light of this background information related to VoD communications in a radio communication system that the significant improvements of the present invention have evolved.